People often, but mistakenly in my view, see two types of links between overpopulation and migration:
- The pressure to migrate from the undeveloped South to the richer North is mainly if not exclusively caused by overpopulation in the South.
- The reason why countries in the North restrict immigration from the South is the fear of overpopulation in the North, resulting from immigration. The relatively healthy economies of the North would not be able to withstand the population shock of major inflows of immigrants, especially given the fact that most immigrants are not high-skilled and tend to be a burden on an economy rather than an asset. Immigration needs to be restricted because it means importing poverty.
I’ll try to argue that both these arguments are wrong and that it is a mistake to link migration to overpopulation in these ways. I’ll start with the first point.
Two things are true about the first argument: migration towards developed countries has increased sharply during the last decades (see here), and population growth in the South has been faster than in the North (see here). What is not true, however, is that the latter has been the cause of the former.
Other social and economic factors, rather than overpopulation, have driven migration. Given the highly regulated nature of migration to the North (green cards, other types of labor certification, visa, border controls etc.), it’s obvious that the people who are able to immigrate are not the poor that are supposedly driven out of their own economies by overpopulation. Only the “jobworthy” who are successful at applying for entry-visas can migrate. (See also here.) And the same is true for illegal immigrants, i.e. those bypassing the regulations. They as well tend to be people who have work prospects in the North, or at least enough money to pay human traffickers.
All this also serves to disprove the second argument above: if migrants in general are not the poorest of the poor, then the second argument doesn’t hold.
However, back to the first argument for a moment. Another economic factor driving migration and completely unconnected to population levels, is the globalization of economic production. Employers in developed countries actively look for relatively cheap workers from the South, and technological improvements in communication, transportation and travel are making this easier.
(One could also point to war and violence as driving forces behind migration, but Malthusians would reply that the real driving force is overpopulation, causing first war and conflict, and then migration. There’s a lot to be said against this, but I’ll keep that for another time).
Regarding the second argument, one can make the following counter-claim. Let’s assume that immigration controls indeed serve the only purpose of keeping people out so as to keep the economy healthy and avoid population shocks which the economy wouldn’t be able to withstand. (Of course, immigration controls in reality serve many other purposes, e.g. pampering xenophobes). If we assume this, we should further assume that existing quotas on immigration (quotas as the result of visa policy, labor permits, family reunion policy etc.) are set in such a way that the number of migrants that are allowed into the country is roughly the number that the economy can sustain. Not higher because then immigration policy would defeat its purpose, but not much lower either because then the restrictions would be unjust and arbitrary.
Given these two assumptions, how do we explain the failure of massive numbers of illegal immigration to destroy host economies? Take for instance the U.S. It’s in an economic crisis right now, but nobody in his right mind claims that immigration is the cause. The U.S. economy was booming for years, and at the same time accommodated millions of legal and illegal immigrants.
To sum up, the tidal wave paranoia of the poor masses of the South engulfing the developed world is just another example of Malthusian hysteria. A simple look at population growth numbers make this abundantly clear. Population has indeed grown more rapidly in the South than in the North (partially because of higher birth rates), but only to return to the same proportion as a few centuries ago. The industrial revolution in the North resulted in more rapid population growth, and the South is now catching up. Fears of growing imbalances and “tsunamis of the poor” aren’t based on facts.